Welcome back! I am delighted to see you again reading with interest!
Let me introduce you to a new series of articles about nanotechnology. The very first one explains what it is, and confirm that it doesn't bite! Are you ready? Here we go!
To define nanoscale and nanomaterials it must be pointed out what nano means. To exhibit this unique nanostructure, materials must have one but the most important feature: at least one of the dimensions has to be smaller than 100 nm. The physical quantities express 10-9 times smaller than the unit, where length (e.g. size, diameter) is measured on the nanometre scale. Clearly, the rest of the physical quantities, such as volume, mass, and energy, maybe far from commonly used prefixes from SI units. In the size range below 1 nm, we can find multiple atoms or molecules which behave differently from individuals. Fullerene, nanotubes, and DNA are excellent examples to present how small a nanoscale is. They can be positioned between the wavelengths of visible/ ultraviolet light and x-ray radiation, but their shape and size cannot be determined by conventional light microscopy.
Unique properties of nanoparticles distinguish them from classic well-known macroscopic materials (bulks) where they have their own disciplines. The materials start to be different because of the effects of quantum confinement and the electrical, thermal and optical properties become significant each. As was mentioned above, atoms located inside bulk materials behave differently than in bulk crystals. They are as small as their physical properties are not constant over their size and that is the reason for description by means of quantum physics.
Nanomaterials have a very high fraction of their atoms on the surface, which belongs to one of the main features. Integrated effects of the forces onto every atom surface provide surface tension and not affect only the underlying nanoscale solid but also the way of interaction with their environment. Such interactions can be turned in order to self-assembly of the spontaneous or direct blocks’ building into the architecture of crystals. However, that nanocrystal is made of atoms that possess impurities and can be missing or misplaced. Those are called point defects, likewise concentration of the single atoms. Such impurities bring or remove electrons to form the solid thus changing its electronic and optical properties occur by a process named doping. It means that creating point defects allows electronic charge to be conducted. Except previously described defects could be featured line and planar defects also. When the position of the entire string of atoms in the lattice is misplaced that shows up as a line defect. When the whole plane of atoms is missing or misplaced those are named as the planar defects. All mentioned defects can interact with each other through coalescence in defect clusters, assemblies of defects with well- defined shapes and housed within the parent lattice. Some of them can be eliminated by controlling the conditions of the nanomaterial growing, e.g. changing the temperature or slowing down the growth speed, while some others are intrinsic and so they a part of the thermodynamic equilibrium system.
Applications of nanoparticles start at bio- areas and ending with industry and daily usage materials. An impact in various branches of every day’s life high- tech industry, include magnetic (or information) storage devices, xerography, and electronics. They are commonly used in computers, stain-resistant clothes, suntan cream, sensors, catalysts, cancer therapy and etc. Besides they are also widely used for thermo- and piezoelectric conversion and solar energy conversion by the solar cell. Might be impossible to count the whole range of usage, but it would be inappropriate to not detail biological and medical application, which will be introduced in the next article!
(Director of Research at Singularity Genesis)